Apparatus for controlling centrifugal formation of sheet material



Nov. 16, 1948. A R. s. AMES ETAL 2,454,116

APPARATUS FOR CONTROLLING CENTRIFUGAL FORMATION OF SHEET MATERIAL' Filed June 14, 1946 2 'sheets-sheet 1 Nu. 16, 194s.

R. s. AMES Er AL i APPARATUS FOR CONTROLLING CENTRIFUGAL FORMATION OF SHEET MATERIAL 2 sheets-sheet 2 Filed June 14, 1946 Patented Nov. 16, h1948 APPARATUS :Fen ooN'rRoLLlNG CEN- MATERIAL vntion relates*to the centrifugal edi-"airti'clesirom 'pla fateriakls; "ulseih observing, deter-i i l g thecritiifwrailformation eff shaped rtifc'les ffrn ith'erifroiplastio sheet' material l f 4'lihe r'ent itiveritiorr-relates to, and Vis espe-4 eiaiirsiiited 'for use tit, the invention Vsiiow-n and des-cribefdinfaiilappl" 'ation of Robert Mayn'e', SeriilfNm 585.504,--`7i11e`d-M1ch 29, 1945, niw Patent No.-2i,448,49`2, 'entitled nMethods and 'apparatus' Ifor 'c'efntr-ifgally forming of Sheet thernroplasties. i the'ceiitrifugal' formation of streamlined articles from fslfieets o-f-ther'rrioaplia'stic mfaterialsl, the edges 'ofthe f'sh'e'etof plastici? inpliabie form, may besecur'ed toa jig orfifiriture whichfin turn mounted on Aa driven lshaft in yradially spaced relation thereto. py'ltheisiifftfs rotation, the'rshet is-grfadlazlily thrown 'or fd'ravvn 'outto form,v aft lone f's'tage, the' 'desiredi y`ailt-iole. Hence, the state of? foirmationfof the plastic sheet -Inust be carefully observed; and ths "frequent-1y is diiicultsince the plastic being formed ,may be transparent `and it is,-cf course, being rotated rapidly about the-shaft. i

The general object of this invention is to pro-f4 vide Yan4 effective sighting device for use with apparatus lf -or centrifugally forming sheet materials. `yAff-urtI-ier 'object of the invention is to provide la sturdy, V-nonore-ailralole, linexpensive sighting arrangement for checking the centrifugal iormation- `of `large articlesfrom plastic materiali "Another object-of the invention is toV shield an operators/eyessubstantially all ofvthe ltime from the light which is yassociated with the -forming apparatus and to permit Vonly intermittent ob-A servation periods. i

Another object of the 'invention is to provid artificial Ilighting for the article being formed which lighting is rotated with the article.

vAnother object of the invention is to employ la etiobos'copic viewing device for'observing th iro i ist 'bei horizontally or otherwise" positioned to fibrin@ 3 vision. The effect is stroboscopic in -that the light 1 comes into View only when the shee-t S is in position to be viewed. The rotation of .the shaft 2 at proper forming speed causes the sheet S to move outw-ardly during which ti-me the light reflection point on the sheet as indicated by the line I8 moves outwardly within the vision of the operator until with the sheet S in fully formed or S1 position the reflection and the `direct line I1 merge at which time rotation of the shaft 2 is stopped or slowed to permit setting of the sheet Without further forming,

Adjustment of the light source 1 and of the rod or of other parts of the apparatus can be made to effect the desired and controlled shaping of the sheet material.

Turning now to the form of the invention illustrated in Figs. 3 and 4, like numerals have been used for like parts except the suffix a has been added. The main feature of difference between thisform of -my invention and that previously described is that instead of holding the light stationary and using a sighting disc, the light source is rotated with the sheet Sa. The light source 'la may be mounted on the jig 5a, for example, at one end thereof. Another manner of mounting is to have the light 1e carried adjustably, as by bracket 9a, on a somewhat more rigid rod 8EL rotatably carried by the shaft 2a. Electric current for lighting the light is supplied by slip rings 20 carried by the shaft 2e.

A sighting rod I32- is adjustably clamped by a bracket I6a to a rod 2| mounted on one end of the base Ia. The rod 2I may be extended horizontally or in other than a vertical position in order to bring the sighting rod I3EL closer to the eye level of the usual operator. Of course, if the rod 2I extends horizontally the rod I'ila will extend vertically.A In this connection it may be noted that in one laboratory formof the apparatus a vertically extending string connected between ceiling and floor was used instead of the rods 2| and |32.

The operation of this form of the invention is very similar to that previously described. The eye Ea of the operator lines up the rod I 3EL and the light l9L on the line Ila. At the same time a light reflection is seen on the line I8, and controlled rotation is continued until the reflection and the main light source verge together. Thereupon rotation is stopped or slowed to prevent further formative movement of the sheet and to insure setting of the sheet in the formed shape.

From the foregoing it will be evident that the objects of the invention have been achieved by the provision of comparatively simple yand inexpensive, rugged, and easily operated apparatus lfor controlling the formation of thermo-plastic sheet materials.

Features of the several embodiments of the invention illustrated and described may be employed in forming Plexiglas and like sheet materials by non-rotative processes. Also, it is possible to combine parts of the inventive forms shown, for example, the sighting disc II of the invention of Figs. 1 and 2 may be included in the embodiment of the invention of Figs. 3 and 4, if desired, and if this is done either the rod I3 or rod I3@ will be omitted.v Instead of employing the sighting disc Il on the form of the invention of Figs. 3 and 4, a metal cover or shield m-ay be used which surrounds the jig or fixture and which is mounted to travel therewith. Such -a cover is spaced from the jig a suiicient distance to permit desired formation of the sheet, with the cover acting to protect the sheet against the air during rotation and to prevent the sheet from ever yig out and hitting someone. A Window or sighting aperture is provided in the cover.

Again, the rods I3 and I3a may be made in the form of edge lighted strips of Plexiglas to increase their visibility. Furthermore, instead of using rods I3 and I3a as sighting means the invention contemplates the use of cords or wires, and, also, the use of buttons or spot type sighting means.

Accordingly, even though the invention has been specifically illustrated and described, all in accord with the patent statutes, it should be specically understood that the invention is not to be limited to the forms disclosed, but that the A scope of the invention is defined in the appended claims.

What is claimed is:

1. Apparatus for forming thermo-plastic sheet material including a. fixture for holding the heat softened sheet material adjacent its edge portions, a light source and a, sighting means in alignment at periodic interv-al to define the outer boundary of the shaped sheet material, said lightsource being positioned to throw a reflection from the sheet material during shaping, and means for centrifugally shaping the sheet material until the reflection is brought into alignment with the light source and the sighting means.

2. Apparatus for forming thermo-plastic sheet material including a fixture for holding the heat softened sheet material adjacent its edge portions, an adjustable light source and an adjustable sighting means in alignment at periodic interval to dene the outer boundary of the shaped sheet material, said light source and sighting means being relatively movable as the sheet is being formed, said light source being positioned t0 throw a reflection from the sheet material at intervals during shaping, and means for centrifugally shaping the sheet material until the reflection is brought into alignment with the light source and the sighting means.

3. Apparatus for forming a heat softened sheet including a jig for supporting edges of the sheet, means for rotatably supporting the jig, an adjustably positioned stationary light source, a sighting disc rotatable with the jig, said disc having a sighting aperture through which the operator can periodically, during the rotation of the disc, see the light source and the reflection of the light source on the sheet being formed, a sighting means adjustably carried in association with the aperture in the sighting disc, said sighting means and light source being aligned to define the line to which the sheet is to be shaped, and means to rotate the jig to centrifugally shape the sheet substantially until the reflection of the light source verges into the line between the light source and the sighting means.

4. Apparatus for forming a heat softened sheet including a jig for supporting edges of the sheet, means for rotatably supporting the jig, a stationary light source, a sighting disc rotatable with the jig, said disc having a sighting aperture through which the operator can periodically, during the rotation of the disc, see the light source and the reection of the light source on the sheet being formed, a sighting means carried in association with the aperture in the sighting disc, said sighting means and light source being aligned to define the line to which the sheet is to be shaped and means to rotate the jig to rcentrifugally shape the sheet substantially until the reflection of the light source verges into the line between the light source and the sighting means.

5. Apparatus for forming a heat softened sheet including a jig for supporting edges of the sheet, means for rotatably supporting the jig, a ra dially adjustable light source mounted for rotaradially adjustable light source mounted for rotation with the jig, said light source being adapted to throw a reflection on the sheet viewable to the operator, an adjustably mounted, stationary sighting means, the light source and the sighting means defining a line viewable to the operators eye and marking the extent to which the sheet is to be shaped, and means for rotating the jig to centrifugally form the sheet substantially until the reflection of the light source verges into the line between the light source and the sighting means.

6. Apparatus for forming a heat softened sheet including a jig for supporting edges of the sheet, means for rotatably supporting the jig, a light source mounted for rotation with the jig, said light source being adapted to throw a reflection on the sheet viewable to the operator, a stationary sighting means, the light source and the sighting means defining a line viewable to the operators eye and marking the extent to which the sheet is to be shaped, and means for rotating the jig to centrifugally form the sheet substan' tially until the reflection of the light source verges into the line between the light source and the sighting means.

7. In apparatus for centrifugally forming pliable sheet materials wherein a strong light is provided to aid in following formation of the article, a shaft, journal means for said shaft, means for rotating said shaft, a fixture adjustably secured to said shaft in axial alignment but radially spaced from said shaft, said fixture being adapted to have the sheet of material to be formed secured thereto so as to support the edges of same but leave the -center portion free for forming movement, and a solid disc of appreciable size carried by said shaft adjacent one end thereof, said disc having a relatively small aperture therein in horizontal and axial alignment with the radially outer section of said fixture whereby a machine operator can stand adjacent to said disc and be shielded from the glare on said apparatus substantially all of the time but can observe the stage of formation of the sheet on the xture through the disc aperture when it is moved past his horizontal line of vision.

8. In apparatus for centrifugally forming transparent thermo-plastic materials, wherein a forming fixture mounted on a rotational support shaft is provided and a strong light is provided thereon, the combination with the rotational support shaft of a sighting disc, said disc being solid to shield the operators eyes from the strong light of the apparatus and being provided with one aperture therein in horizontal and axial alignment with the forming fixture of the apparatus so that the operator can obtain an instantaneous sight of the fixture as the aperture in the disc is moved past his line of vision.

9. In vcentrifugal forming apparatus for thermo-plastic materials wherein a forming flxture and a rotational support therefor are provided, the combination with the rotational support of a sighting disc, said disc .being opaque and being provided with one aperture therein in horizontal and axial alignment with the radially outer section of the forming fixture of the apparatus.

ROBERT S. AMES. MAURITZ P. PETERSON. JOHN C. FELDSCHER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 765,570 Fenn July 19, 1904 1,706,857 Mathe Mar. 26, 1929 2,076,058 Anderson Apr. 6, 1937 2,367,642 Helwig Jan. 16, 1945 Certificate of Correction Patent No. 2,454,116. November 16, 1948.

ROBERT S. AMES ET AL.

. v It is hereby certied that error appears in the printed specification of the above numbered patent requiring correction as fellows:

Column 5, line 7, strike out the Words and syllable radially adjustable light source mounted for rota;

THOMAS F. MURPHY,

Assistant Oommzssz'oner of Patents. 

